High conductivity polyaniline compositions and uses therefor

ABSTRACT

The present invention describes compositions formed from polyanaline and carbon nanotubes, which exhibit enhanced conductivity and which provide uses in electronic circuit applications.

FIELD OF THE INVENTION

[0001] The present invention describes compositions formed frompolyanaline and carbon nanotubes, which exhibit enhanced conductivityand provide high utility in novel applications in electronic circuits.

TECHNICAL BACKGROUND OF THE INVENTION

[0002] Conductive polymers have long been known in the art, includingpolyacetylene, polypyrrole, poly(para-phenylene), and derivativesthereof. While in some cases exhibiting metallic-like conductivity,highly conductive polymers have been limited in their practicalapplications because they are typically chemically unstable in use, andvirtually intractable, being unsuited for either solution or meltprocessing. All conductive polymers require acid or oxide functionality,usually referred to as doping, to achieve their high conductivities.

[0003] Polyaniline (PANI) stands out among conductive polymers in thatit is known in the art to be chemically stable and readily soluble inconventional, environmentally friendly solvents, and thus offers thepossibility for employing ordinary means known in the art formingcoatings, films and sheets, fibers, printed patterns, and so forth.

[0004] Conductive PANI is described in great detail in Chiang et al,Synthetic Metals, 13 (1986), pp. 193-205. Chiang et al disclose numerousPANI compositions, identifying the protonic acid doped emeraldinenitrogen base salt, as the most highly conductive form, with aconductivity of 5 S/cm. This conductivity remains well below the 10²S/cm range characteristic of certain other conductive polymers, andwhich represents practical threshold conductivity for widespread utilityin electronics.

[0005] Levon et al, Polymer 36, pp 2733ff (1995) and Ahiskog et al,Synthetic Metals, 69, pp 135ff (1995) disclose formation of the PANInitrogen base salt at elevated temperature by combining with liquidorganic acids such as dodecylbenzenesulfonic acid (DBSA).

[0006] There is considerable incentive to find a way to enhance theconductivity of PANI while preserving the desirable chemical stabilityand processibility thereof. Specifically, a PANI composition exhibitinga conductivity of ca. 10² S/cm may be a highly preferred material forimportant applications in electronics.

[0007] It is known in the art to combine PANI with inorganic fillers,including conductive fillers such as graphite, metal fibers, andsuperconducting ceramics, see for example Jen et al, U.S. Pat. No.5,069,820.

[0008] Carbon nanotubes are a relatively new form of matter related toC₆₀ the spherical material known popularly as “Buckminster Fullerene”While new, carbon nanotubes have elicited much interest because of theirunusual structure and are available commercially. They are described inconsiderable detail in Carbon Nanotubes and Related Structures, by PeterJ. F. Harris, Cambridge University Press, Cambridge, UK (1999).

[0009] Composites of conductive polymers and carbon nanotubes in theform of films are disclosed in Coleman et al, Phys. Rev. B 58 (12)R7492ff (1998), Chen et al, Advanced Materials 12 (7) 522 ff (2000), andYoshino et al, Fullerene Sci. Tech. 7 (4) 695ff (1999).

[0010] Coleman et al, op. cit. discloses composites ofpoly(p-phenylenevinylene-co-2,5dioctoxy-m-phenylenevinylene) (PMPV) withcarbon nanotubes produced by an electric arc procedure. Mass fractionsof nanotubes plus residual soot ranged from ca. 0.5-35%. Films werespin-coated onto a platinum surface from a toluene solution.Conductivity is shown to exhibit a six order of magnitude increasebetween ca. 4% and ca 9% nanotubes.

[0011] Also disclosed in Coleman et al, op. cit., is a failed attempt tomake a similar composite with PMMA. The failure is said to result frommolecular conformational causes.

[0012] Chen et al, op. cit., disclose composite films of nanotubes andpolypyrrole. Both films and coated nanotubes are disclosed. Thenanotubes are shown to enhance the conductivity of the polypyrrole. Thefilms are deposited by exposing various substrates to a solution ofpyrrole and nanotubes followed by electropolymerization of the pyrrolein situ on the substrate, thus entrapping the nanotubes within thepolymer matrix. Chen also employs arc-grown nanotubes.

[0013] Yoshino et al, op. cit., disclose composites ofpoly(3-hexylthiophene) (PAT6) and nanotubes produced by chemical vapordeposition and purified. The nanotubes were dispersed in hexene andmixed with the chloroform solution of the polymer. Films were formed bycasting on a quartz plate. A ca. 4 order of magnitude change inconductivity was observed between a volume fraction of ca. 1% to ca.10%, with the percolation threshold estimated to be at ca. 5.9%.

[0014] Laser thermal ablation image transfer technology for colorproofing and printing is described in Ellis et al, U.S. Pat. No.5,171,650 and elsewhere. Similar methods are in current commercial usein the printing and publishing businesses.

SUMMARY OF THE INVENTION

[0015] The present invention provides for a composition comprising anitrogen base salt derivative of emeraldine polyaniline and carbonnanotubes.

[0016] The present invention further provides for electronic circuitscomprising conductive pathways of a nitrogen base salt derivative ofemeraldine polyaniline and carbon nanotubes.

[0017] The present invention further provides for a process fordepositing conductive pathways from a donor element onto a receiversubstrate contiguous with the donor element, wherein the donor elementis a layered structure comprising a support layer capable of partiallyabsorbing laser radiation, one or more heating layers, and an imagingtopcoat transfer layer, and, optionally, an ejection layer, the processcomprising:

[0018] (a) exposing said support layer to incident laser energy;

[0019] (b) converting said laser energy to heat in said one or moreheating layer(s) that is (are) contiguous with the topcoat that absorbssaid laser energy;

[0020] (c) said heat applied to said topcoat being sufficient to effecta transfer of at least a portion of said topcoat to a receiving surface;

[0021] wherein the topcoat is a conductive PANI/nanotube composite.

BRIEF DESCRIPTION OF DRAWINGS

[0022]FIG. 1 shows a schematic of the laser deposition apparatus used toform electronically conductive pathways on a substrate.

[0023]FIG. 2 is a pixelated image generated using computer aidedsoftware. The image was translated into a pattern of pixels as furtherdescribed herein.

[0024]FIG. 3 represents an image showing a close-up of source and drainsand an intervening channel.

DETAILED DESCRIPTION

[0025] The present invention describes compositions comprisingpolyaniline and carbon nanotubes that exhibit electronic conductivitiesof ca. 10² S/cm while retaining the desirable chemical stability andsolution processibility of polyaniline. The compositions of the presentinvention are highly suitable for preparation as coatings deposited insolution/dispersion form on substrates. In a preferred embodiment, theso-deposited coating is employed as a thermal image transfer medium,enabling the formation thereby of conductive pathways in electroniccircuits.

[0026] In the practice of the present invention the emeraldine form ofPANI, wherein the PANI is made up of alternating units of the oxidizedand reduced form of the monomer, as described in detail in Chiang et al,op. cit., is treated according to the method of Chiang et al with aprotonic acid to form a nitrogen base salt. According to one method, thewater-insoluble emeraldine base is dispersed in an aqueous protonic acidsuch as HCl, followed by drying to form a conductive powder. However, itis preferred to combine the emeraldine base with a liquid organic acid,such as dodecylbenzenesulfonic acid (DBSA), to form an organic saltwhich is soluble in common solvents such as toluene, xylene, and otheraromatic solvents. In order to achieve a high level of conductivity, theemeraldine base should be combined with liquid acid at a temperature of80-150° C. In the case in which the acid is in molar deficit all acidbecomes consumed in the protonation of the PANI base units and thesystem is thus composed of protonated and unprotonated PANIconstitutional units. In contrast with acid in molar excess, all PANIbase becomes protonated and the mixture is composed of the protonatedPANI and excess acid. An excess of acid promotes solubility but may havedeleterious effects on electronic properties.

[0027] One of skill in the art will appreciate that the unexpectedeffects and benefits of the present invention may not be realized withevery protonated PANI, however formed. It is found in the practice ofthe present invention that certain protonated PANI compositions arehighly effective while others are ineffective, as shown hereinbelow inthe specific embodiments hereof.

[0028] Both single-walled and multi-walled nanotubes are known in theart, and either is suitable for the practice of the present invention.Furthermore, the caps present at the ends of the tubes may be reduced bytreatment with oxidizing acids (Tsang et al. Nature, 372, (1994) 1355)such as nitric acid, which inevitably creates surface acid sites whichare used to protonate the PANI. There are several methods employed inthe art for producing nanotubes. Regardless of the method employed, itis preferred that the carbon nanotubes be relatively free ofcontaminating matter. Purities of over 90% by weight are preferred.Single-walled nanotubes are preferred.

[0029] One of skill in the art will understand that the exactconcentration of nanotubes needed to achieve the requisite increase inconductivity will depend, among other things, on the degree to which thePANI has been converted to the nitrogen base salt, the particularnanotubes employed, and the target conductivity. In the composition ofthe invention, a concentration of nanotubes between 0.5% and 30% byweight is suitable with a concentration between 1% and 10% preferred,with 1% to 5% most preferred. At concentrations below 0.5% littlepractical increase in conductivity is anticipated. Concentrations above30% are expected to adversely affect the physical properties of thecomposite. Nanotubes are expensive, at present; it is not desirable toemploy more than the minimum number of nanotubes needed to achieve thedesired enhancement of conductivity.

[0030] It has been found satisfactory in the practice of the inventionto form the composite of the invention by dissolving the nitrogen basesalt of an organic acid such as DBSA or DNNA in an aromatic solvent suchas toluene or xylene at a concentration of ca. 5-15% by weight and thenmixing the solution with a dispersion of carbon nanotubes in the same ora miscible second solvent. The concentration of nanotubes in thedispersion is ca. 0.5-10% by weight. The weight ratio of nanotubes topolymer in the composite may be controlled by simply controlling therelative amounts of the solution and dispersion employed. The dispersionof nanotubes has been found to achieve satisfactory homogeneity afterbeing subject to ultrasonic agitation for 10 to 30 minutes, preferably20 minutes at room temperature. After the nanotube dispersion andpolymer solution are combined, they are subject to ultrasonic agitationfor 2.5 to 10 minutes, preferably 5 minutes. After mixing, thedispersion so formed can then be cast onto a substrate using anyconventional method known in the art. A preferred method is to spreadthe mixture onto a substrate such as a polyester film and to use adoctor blade to produce a coating of uniform thickness. The coating isthen subject to vacuum extraction to remove the solvent, leaving behinda solid coating of the composite of the invention.

[0031] One particularly preferred use of the composite of the presentinvention is as a conductive pathway in electronic circuits, saidconductive pathway being produced by laser thermal transfer imaging. Inlaser thermal transfer imaging a donor element is used to transfer animage onto a receiver element upon exposure of the donor element to asequence of laser pulses describing a pattern which imparts to thetransferred image the desired form and resolution.

[0032] The donor element is a layered structure comprising a supportlayer, preferably a flexible support layer, a heating layer, and atransfer layer. In one embodiment, the support layer is sputter-coatedwith a thin layer of metal, which in turn is solution coated with alayer of the PANI/NT composite of the present invention.

[0033] In use, the thin metal heating layer absorbs incident laserradiation converting it into heat thereby causing the partialdecomposition of any organic matter proximate to the point of laserincidence which, in turn, propels the PANI/NT layer onto a receiversubstrate. The organic matter may include the polymeric substrate, anoptional separate organic “ejection layer” specifically selected for itsrapid decomposition into gaseous by-products and the PANI/NT transferlayer itself. It is the decomposition of portions of the organic matterproximate to the heating layer that produces rapidly expanding gaseouslow molecular weight components which provide the propulsive force topropel the adjacent portion of the PANI/NT layer to the receivingelement. The laser can be scanned across the coated surface of the donorelement, turned on and off according to a preprogrammed pattern, therebyforming a high precision image on the receiving surface.

[0034] Laser thermal ablation transfer imaging is well-known in the artof color proofing and printing, as described, for example, in Ellis etal, U.S. Pat. No. 5,171,650, which is herein incorporated by referenceto the entirety. It is a completely surprising result that the method ofEllis et al can be adapted in its entirety to the production ofconductive polymer pathways by substituting the PANI/nanotube compositeof the present invention for the pigmented layer in Ellis et al. In thepresent invention, a donor element comprises a support substrate (i), alayer capable of partially absorbing a high power pulse of laserradiation and rapidly converting said absorbed laser radiation to heatwithin the confines of a sufficiently small area so as to effect thetransfer of an image of acceptable resolution onto the receiving surface(ii), an imaging topcoat (iii) essentially coextensive with saidradiation absorbing layer, said imaging topcoat (iii) comprising thehighly conductive PANI/nanotube composite of the present invention. In asecond embodiment, a specially tailored optional organic ejection layeris also included in order to enhance the speed and precision of theresponse to the laser pulse.

[0035] In the practice of the invention said radiatively absorbing layer(ii) absorbs incident laser energy which is applied at a rate sufficientto transfer the carrier topcoat (iii) to a receiving surface, and isapplied within sufficiently narrow confines that the image formed on thereceiving surface is of sufficient resolution for the intended purpose.Resolution of 1 micrometer is readily achievable by this method.

[0036] For the laser beam to heat, the incoming radiation must beadsorbed. The optical absorption of the metal layer is critical. If themetal layer is too thick it reflects the incident radiation; if it istoo thin it transmits the radiation. There is an optimum thickness formaximum absorption of the incoming radiation. This is determined by thedielectric constant of the specific metal layer at the laser wavelength.In the practice of the invention, a thickness of ca. 10 nanometers of Nihas been found to be satisfactory.

[0037] The receiving surface is in direct and intimate contact with theimaging topcoat of the transfer medium.

[0038] In the practice of the invention, Mylar® polyester film has beenfound to be a satisfactory substrate for the laser thermal transfermedium of the invention. Other suitable substrates will includepolyvinylchloride, polypropylene and polyethylene. There are noparticular limitations on the substrate except that they must bepolymeric and transparent to the incident laser radiation.

[0039] Satisfactory results can be achieved without a separate organicejection layer, utilizing only a support layer, a heating layer, and aPANI/NT transfer layer, wherein the interface at the heating layer ispartially decomposed to form the gaseous decomposition productsnecessary to propel the PANI/NT. However, a separate organic ejectionlayer is preferred.

[0040] Polymers, especially polymers having a decomposition temperaturebelow that of the PANI/NT composite, are preferred for use in theorganic ejection layer which is preferred in the practice of theinvention. Suitable polymers include polycarbonates such aspolypropylene carbonate; substituted styrene polymers such aspoly(alpha-methylstyrene); polyacrylate and polymethacrylate esters,such as polymethylmethacrylate and polybutylmethacrylate; cellulosicmaterials such as cellulose acetate butyrate and nitrocellulose;polyvinyl chloride; poly(chlorovinyl chloride); polyacetals;polyvinylidene chloride; polyurethanes with decomposition temperaturesof about 200° C.; polyesters; polyorthoesters; acrylonitrile andsubstituted acrylonitrile polymers; maleic acid resins; and copolymersof the above. Mixtures of suitable polymers can also be used. Preferredpolymers for the ejection layer are polyacrylate and polymethacrylateesters, nitrocellulose, poly(vinyl chloride) (PVC), and chlorinatedpoly(vinyl chloride) (CPVC). Most preferred are poly(vinyl chloride) andchlorinated poly(vinyl chloridelt is in some instances satisfactory toemploy the polymeric ejection layer as the support layer as well,thereby eliminating an entire layer in the structure of the donorelement; however it is preferred to use two different layers. While thebest arrangement will vary depending upon the exigencies of the specificapplication, in general the total thickness of the ejection layer andsupport layer should be in the range of 1-3 micrometers. When a separatesupport layer is employed, an ejection layer of less than 25 micrometersis satisfactory, but there needs to be enough to provide adequateablation of the PANI/NT layer (the ablated region is 0.2-0.3 microns).

[0041] Other materials can be present as additives in the ejection layeras long as they do not interfere with the essential function of thelayer. Examples of such additives include plasticizers, coating aids,flow additives, slip agents, antihalation agents, antistatic agents,surfactants, and others which are known to be used in the formulation ofcoatings. In the embodiments of the invention wherein such additives aredesirable, it is particularly preferred that there be an ejection layerwhich is distinct from the PANI/NT composite itself.

[0042] The heating layer preferably absorbs 2040% of the incident laserradiation, and is capable of sustaining an extremely rapid rise intemperature at the point of incidence of the laser pulse. In a preferredembodiment the heating layer is deposited on the flexible ejectionlayer. Materials suitable for the heating layer can be inorganic ororganic and can inherently absorb the laser radiation or includeadditional laser-radiation absorbing compounds. Inorganic materials arepreferred.

[0043] Suitable inorganic materials include transition metals, metals,and non-metals, including elements of Groups IIIa, IVa, Va, Via, VIII,IIIb, and Vb of the periodic table of elements, their alloys with eachother, and their alloys with the elements of Groups Ia and IIa. Carbonis a suitable non-metal. Metals are preferred. Preferred metals includeAl, Cr, Sb, Ti, Bi, Zr, Ni, In, Zn, and their oxides, suboxides andsuitable alloys. More preferred are Al, Ni, Cr, Zr and C. Most preferredare Al, Ni, Cr, and Zr.

[0044] The thickness of the heating layer is generally about 20Angstroms to 0.1 micrometer, preferably about 50 Angstroms for Al and 80Angstroms for Cr. The specific thickness of the metal layer is chosenbased on that providing the maximum absorption at the laser wavelength.Therefore, the metal thickness is dependent on the specific dielectricconstant of each metal.

[0045] Although it is preferred to have a single heating layer, it isalso possible to have more than one heating layer, and the differentlayers can have the same or different compositions, as long as they allfunction as described above. The total thickness of all the heatinglayers should be in the range given above, i.e., 20 Angstroms to 0.1micrometer.

[0046] The heating layer(s) can be applied using any of the well-knowntechniques for providing thin metal layers, such as sputtering, chemicalvapor deposition, and electron beam deposition.

[0047] The PANI/NT composition of the present invention is depositedupon the metallic coating preferably by solution casting from toluene orxylene, applied via a Meyer rod, to a dried film thickness ranging from0.3 to 3 microns, preferably 1 micrometer.

[0048] The donor element thus formed is positioned on the receivingsurface, the PANI/NT coating being directly in contact to the receivingsurface. The opposite surface of the donor element is then subject tolaser irradiation in a pattern of pulses which causes the ejection ofPANI/NT from the transfer medium and onto the receiving substrate in thedesired pattern. Suitable laser irradiation includes infrared diodelaser irradiation in the wavelength range of 780 nm to 850 nm atincident fluences of 100 mJ/cm2 to 400 mJ/cm2 delivered in a pulse ofabout 1 microsecond duration. Incident laser fluence must besufficiently high to effect ejection of a PANI/NT “pulse” but not sohigh that degradation of the PANI/NT material is initiated

[0049] Suitable receiving surfaces include polymethacrylate andpolymethacrylate co-polymer. Typical coatings of the receiver arecopolymers of methyl methacrylate, butyl methacrylate and glycidylmetacrylate, styrene and polycaprolactone coated onto a polyestersubstrate or can be free standing.

[0050] In a preferred embodiment, the patterned layer of PANI/NT is usedas source and drain of a plastic transistor wherein the semiconducting,dielectric and gate will be sequentially deposit to complete thecircuit.

[0051] The present invention is further described according to thefollowing specific embodiments.

EXAMPLE 1

[0052] The PANI-DBSA material was supplied by UNIAX Corporation (SantaBarbara, Calif.) in a 9% solids solution in toluene. Single wall carbonnanotubes, manufactured by pulsed laser vaporization of a metal/carbontarget in a furnace at 1100° C., were purchased from Rice University.The nanotubes were purified to greater than 90% purity by rinsing innitric acid, water and toluene. The main impurity was leftover Ni/Cocatalyst particles. The carbon nanotubes ranged between 0.2 and 2microns in length.

[0053] The nanotubes were dispersed in toluene at 1.43% by weight. Thecarbon nanotubes slurry was prepared by adding 0.286 g of carbonnanotubes and 19.714 g of Toluene into a 2 oz container. The mix wasthen subject to ultrasonic agitation for 20 minutes while maintaining avortex in the slurry. Appropriate amounts of the slurry were added tothe specific amount of 9% Pani/DBSA solution needed to achieve thedesired nanotubes concentration in the dry film, and the mixture subjectto ultrasonic agitation for 5 minutes. The amounts of slurry andDSBA/PANI solutions were adjusted as follows to give the desirednanotube TABLE 1 Example 1 Specimens Weight of 1.43% % NanotubeNanotubes Weight of slurry in in Specimen 9% DSBA/PANI Toluene dry filmControl 10 0 0 Specimen 1A 11.0834 0.1748 0.25 Specimen 1B 11.055 0.34960.5 Specimen 1C 11.0277 0.5244 0.75 Specimen 1D 11.000 0.6993 1.00Specimen 1E 10.972 0.8741 1.25 Specimen 1F 10.944 1.0489 1.50 Specimen1G 10.916 1.2237 1.75 Specimen 1H 10.888 1.3986 2.00

[0054] These dispersions were coated onto 2″×3″ glass microscope slidesusing a #4 Meyer rod which are well known in the art for hand coatingfilms from solution and dried in air in an oven at 60° C. for 45seconds. The coated area was 1″×2″ and the film thickness around 4microns. Thickness was determined by optical interferometry.

[0055] A line of four {fraction (1/16)}″ by 3″ 4000 Å thick silvercontacts 0.25″ apart were sputtered through an aluminum mask on to thethus prepared film using a Denton vacuum unit (Denton Inc. Cherry Hill,N.J.). The film resistivity was measured using the standard 4-probemeasurement technique in which a current is applied to the two outercontacts and the voltage across the two inner contacts is determined.The current was supplied by a Hewlett Packard 6234A dual output powersupply and was measured using an electrometer (Keithley 617). Thevoltage was measured at the two inner contacts using a Keithleymiltimeter. The resistivity, ρ, was calculated as:$\sigma = {\frac{1}{\rho} = \frac{i \times d}{V \times A}}$

[0056] Where ρ is the resistivity in (ohm-cm), V is the voltage measuredat the inner contacts, i is the current at the 2 outer contacts, d isthe separation between the inner contacts, and A is the cross-sectionalarea of the film determined from the product of the distance between theouter contacts and the film thickness. The conductivity for each film isshown in Table 2 and depicted graphically in FIG. 1. TABLE 2 Specimen NTconc σ (S/cm) Control 0 0.00018 Specimen 1A 0.25 0.00025 Specimen 1B 0.50.00017 Specimen 1C 0.75 52 Specimen 1D 1 62 Specimen 1E 1.25 62.539Specimen 1F 1.5 39 Specimen 1G 1.75 36.7 Specimen 1H 2 44

COMPARATIVE EXAMPLE 1

[0057] A 2.60 wt. % solution of the conducting polyaniline use in thisexample was prepared by mixing 14.36 g mixed xylenes (EM Science,purity: 98.5%) to 0.9624 g XICP-OSOI, a developmental conductivepolyaniline solution obtained from Monsanto Company. XICP-OSOI containsapproximately 48.16 wt. % xylenes, 12.62 wt. % butyl cellosolve, and41.4 wt. % conductive polyaniline wherein the nitrogen base salt wasprepared by treating the PANI with dinonylnaphthalenic acid (DNNA).

[0058] Nanotubes were dispersed in turpinol at 1.43% by weight. Thenanotube/turpinol mixture was subject to ultrasonic agitation for 24hours at ambient temperature prior to mixing with the 41.4% solution ofXICP-OSOI. PANI-XICP-OSO1/NT dispersions were made at ratios to givenanotube/total solids concentration ratios 0, 0.25, 0.5, 0.75, 1, 1.25,1.5, 1.75, 2, 4, 6, 10, 20 and 40% were coated onto 2″×3″ glassmicroscope slides and dried in air at 60° C. for 30 seconds.

[0059] The coated area was 1″×2″. Film thickness was determined byoptical interferometry. Silver contacts for resistivity measurementswere sputtered to 4000 Å in thickness through an aluminum mask using aDenton vacuum unit (Denton Inc. Cherry Hill, N.J.). The film resistivitywas determined according to the method of Example 1. The resistivityversus nanotube concentration is shown in Table 3. TABLE 3 NT conc.Specimen (%) σ (S/cm) Control 0 0.000306 Specimen CE1A 0.25 0.00048Specimen CE1B 0.5 0.0068 Specimen CE1C 0.75 0.015 Specimen CE1D 1 0.114Specimen CE1E 1.5 0.3698 Specimen CE1F 2 1.31 Specimen CE1G 2.5 1.27Specimen CE1H 4 1.53 Specimen CE1I 6 1.08 Specimen CE1J 8 1.9 SpecimenCE1K 10 1.87 Specimen CE1L 20 3.37 Specimen CE1M 40 27.53

EXAMPLE 2

[0060] Laser thermal ablation transfer was employed to create anelectronic circuit component with a PANI/nanotube composition.

[0061] A donor layer was formed by coating a 10 nanometer thick layer ofmetallic nickel onto 400D Mylar® by electron-beam deposition. The thusformed Ni layer exhibited 35% optical transmission at a wavelength of830 nm. A transfer layer was formed by coating the thus formed Ni layerwith a 1 micrometer thick layer of the composition of ComparativeExample 1 designated CE1J using a #4 Meyer rod.

[0062] The receiving layer consisted of a 1 micrometer thick layer ofpolythiophene coated onto 400D Mylar® from a 2% solids solution intoluene with a #4 Meyer rod. The coating was air dried for 30 minutes.

[0063] The image shown in FIG. 2 was generated using computer aideddesign software. The image was translated into a pattern of pixels whichwere designated either “on” or “off” to correspond respectively toactivation and deactivation of the laser to be employed for imagetransfer.

[0064] The images were obtained using a Spectrum CREO Trendsetter with5080 DPI resolution (CREO-Scitex, Vancouver, Canada) equipped with aSpectrum Trendsetter Exposure Unit comprising a 20 watt infrared diodelaser emitting 1 microsecond pulses at a wavelength of 830 nanometers.The Spectrum CREO Trendsetter comprised an 81.2-cm long drum having aperimeter of 91 cm. The receiver and donor elements were loaded intoseparate cassettes which is placed into the unit. Prior to exposure thereceiver was automatically loaded from the cassette onto the drum andheld by vacuum. The donor, slightly larger than the receiver, was thenautomatically loaded from the cassette and positioned directly on top ofthe receiver and held by vacuum at all four edges.

[0065] The pixelated image of FIG. 2 was loaded into the controlcomputer of the CREO unit, and the donor was then exposed according tothe programmed pattern with the desired pattern. To form the image, thelaser beam was split by a light valve to form an array of 240 5×2micrometer overlapping pixels. The laser head was translated along thedrum and each pixel was turned on or off to form the image. The laserfluence was adjustable 7 Watts and the drum speed was 150 RPM. The scaleof FIG. 2 is 5 cm in width and 9 cm in height. Five mm gates are shownat (2), 2 mm gates are shown at (4) and 1 mm gates are shown at (6).Twenty μ channels are shown at (8). A 1 mm wide source is shown at (10);a 2 mm wide source is shown at (12) and a 5 mm wide source is shown at(14).

[0066] After exposure the image of FIG. 2 had been transferred to thereceiver in the form of a PANI/nanotube “ink”. FIG. 3 is an imageshowing a close-up of a source (16), drain (18), and intervening channel(20). The channel (20) was 20 micrometers wide, as shown.

What is claimed is:
 1. A composition comprising a nitrogen base saltderivative of emeraldine polyaniline and carbon nonotubes.
 2. Thecomposition of claim 1 wherein the nanotubes are single-walled.
 3. Thecomposition of claim 1 wherein the nanotubes are multi-walled.
 4. Anelectronic circuit comprising one or more conductive pathways of anitrogen base salt derivative of emeraldine polyaniline and carbonnanotubes.
 5. A process for depositing conductive pathways from a donorelement onto a receiver substrate contiguous with the donor element,wherein the donor element is a layered structure comprising a supportlayer, one or a plurality of heating layers capable of partiallyabsorbing laser radiation, and an imaging topcoat transfer layer, and,optionally, an ejection layer, the process comprising: (a) exposing saidsupport layer to incident laser energy; (b) converting said laser energyto heat in the one or plurality of heating layer(s) that is (are)contiguous with the topcoat and that absorbs said laser energy; (c) saidheat applied to said topcoat being sufficient to effect a transfer of atleast a portion of said topcoat to a receiving surface; wherein thetopcoat is a conductive PANI/nanotube composite.
 6. The process of claim5 wherein the heating layer is carbon.
 7. The process of claim 5 whereinthe heating layer is a metal and is selected from the group consistingof Al, Cr, Sb, Ti, Bi, Zr, Ni, In, Zn, and their oxides, suboxides andalloys.